MSE Colloquium: Ashwin Shahani, Peering into the solidification of polyphase patterns
2040 Fontana Labs
140 W. 19th Ave
Columbus, OH 43210
United States
Dr. Ashwin Shahani
University of Michigan
Abstract
Peering into the solidification of polyphase patterns
Understanding the solidification of microstructure is the key to controlling it. This is particularly true for eutectics, which exhibit outstanding mechanical or electrical properties because their polyphase microstructures act as natural composite materials. The eutectic phases may be arranged in cells or colonies, giving rise to a structural hierarchy in the nanometer to micrometer regime. It remains to be determined how the eutectic pattern develops in strongly anisotropic systems and how it supports diffusional instabilities caused by solute segregation. Motivated by recent developments in synchrotron-based X-ray “live” imaging, we capture in situ and for the first time the solidification dynamics of eutectics along a univariant path. We extract information on the structure and dynamics of solid-liquid and solid-solid interfaces with the aid of machine learning techniques. The results enable us to test the predictions of simulations and theory and suggest new avenues for the expansion of theory. Our studies provide a first glimpse into the effects of an interfacial energy anisotropy on the origin of complex patterns, with implications to the design of novel microstructures.
Biography
Dr. Ashwin J. Shahani has served as Assistant Professor in the Department of Materials Science and Engineering at the University of Michigan since 2016. He earned his BS degree from Cornell University and his PhD degree from Northwestern University, both in the field of Materials Science and Engineering. His research group specializes in the development and application of in situ characterization methods for the study of phase and structural transformations in a wide range of materials — both periodic and aperiodic, metal and intermetallic. Their research has broad, technical impact on the manufacture of tailored microstructures via processing. Shahani has won young investigator awards from AFOSR in 2017, ARO in 2018, and NSF in 2019.
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